Forecasting the global need for high-dose methotrexate to prevent and mitigate shortages.

6571 Background: Causes of drug shortages in low-income and middle-income countries are numerous and often more than one cause contributes. Shortages are especially problematic when they involve drugs like high-dose methotrexate (HDMTX), which is required for several highly curable cancers and has no good substitute. Morocco is currently experiencing a national shortage of high-dose methotrexate that has so far lasted several months and has impacted the care of all patients whose protocol includes HDMTX. In this case, a single supplier left the market due to government-imposed pricing that made continued sales increasingly unprofitable. Practicing hematologist/oncologists in Myanmar, the Philippines, Vietnam, and Cambodia also reported shortages that reached patients during 2018. Methods: We created a forecasting model to identify the total annual national need for HDMTX and number of patients based on incidence by age, age distribution, and numbers of doses in typical protocols for osteosarcoma, primary CNS lymphoma, pediatric B-cell NHL, and ALL, curable cancers for which HDMTX is essential. Results: More than 200,000 patients per year need HDMTX (approximately 950,000 doses, see Table). 86% of these live in low- and middle-income countries, where access to inexpensive generic drugs is especially important. Conclusions: This forecasting tool will facilitate national purchasing and negotiating to assure continuous supply of HDMTX. It can be adapted for other drugs, and is especially relevant for low-cost generic drugs, which are disproportionately affected by shortages. [Table: see text]